I'm also having this problem.
Our main business software creates and opens pdf documents and the user can choose whether to "save as" (since the displayed file is only a temp file), print or email the document.
The lack of "save as" toolbar button in version X prevents me (as the sysadmin) from deploying it on my company's desktop since it's an essential button for us.
I'm aware of the option to Shift+Ctrl+S or just File > "Save as" but in our case it's an annoying time waster.
No, you can't (at least not without a plugin). The only tools you can add to the system bar in Adobe Reader X are the ones you can see when you right-click the toolbar, and "Save As" isn't on the list, because it's a submenu not an item.
Thanks for your reply.
1. Is there a plugin for this?
2. How can one let adobe know that this feature is important to them so it might be fixed in future releases?